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   1 /*  $Id: signal.c,v 1.60 2002/02/09 19:49:31 davem Exp $
   2  *  arch/sparc64/kernel/signal.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *  Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
   6  *  Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
   7  *  Copyright (C) 1997 Eddie C. Dost   (ecd@skynet.be)
   8  *  Copyright (C) 1997,1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
   9  */
  10
  11 #ifdef CONFIG_COMPAT
  12 #include <linux/compat.h>       /* for compat_old_sigset_t */
  13 #endif
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/signal.h>
  17 #include <linux/errno.h>
  18 #include <linux/wait.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/unistd.h>
  21 #include <linux/mm.h>
  22 #include <linux/tty.h>
  23 #include <linux/binfmts.h>
  24 #include <linux/bitops.h>
  25
  26 #include <asm/uaccess.h>
  27 #include <asm/ptrace.h>
  28 #include <asm/pgtable.h>
  29 #include <asm/fpumacro.h>
  30 #include <asm/uctx.h>
  31 #include <asm/siginfo.h>
  32 #include <asm/visasm.h>
  33
  34 #include "entry.h"
  35 #include "systbls.h"
  36
  37 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  38
  39 /* {set, get}context() needed for 64-bit SparcLinux userland. */
  40 asmlinkage void sparc64_set_context(struct pt_regs *regs)
  41 {
  42         struct ucontext __user *ucp = (struct ucontext __user *)
  43                 regs->u_regs[UREG_I0];
  44         mc_gregset_t __user *grp;
  45         unsigned long pc, npc, tstate;
  46         unsigned long fp, i7;
  47         unsigned char fenab;
  48         int err;
  49
  50         flush_user_windows();
  51         if (get_thread_wsaved()                                 ||
  52             (((unsigned long)ucp) & (sizeof(unsigned long)-1))  ||
  53             (!__access_ok(ucp, sizeof(*ucp))))
  54                 goto do_sigsegv;
  55         grp  = &ucp->uc_mcontext.mc_gregs;
  56         err  = __get_user(pc, &((*grp)[MC_PC]));
  57         err |= __get_user(npc, &((*grp)[MC_NPC]));
  58         if (err || ((pc | npc) & 3))
  59                 goto do_sigsegv;
  60         if (regs->u_regs[UREG_I1]) {
  61                 sigset_t set;
  62
  63                 if (_NSIG_WORDS == 1) {
  64                         if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0]))
  65                                 goto do_sigsegv;
  66                 } else {
  67                         if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t)))
  68                                 goto do_sigsegv;
  69                 }
  70                 sigdelsetmask(&set, ~_BLOCKABLE);
  71                 spin_lock_irq(&current->sighand->siglock);
  72                 current->blocked = set;
  73                 recalc_sigpending();
  74                 spin_unlock_irq(&current->sighand->siglock);
  75         }
  76         if (test_thread_flag(TIF_32BIT)) {
  77                 pc &= 0xffffffff;
  78                 npc &= 0xffffffff;
  79         }
  80         regs->tpc = pc;
  81         regs->tnpc = npc;
  82         err |= __get_user(regs->y, &((*grp)[MC_Y]));
  83         err |= __get_user(tstate, &((*grp)[MC_TSTATE]));
  84         regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
  85         regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
  86         err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1]));
  87         err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2]));
  88         err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3]));
  89         err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4]));
  90         err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5]));
  91         err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6]));
  92         err |= __get_user(regs->u_regs[UREG_G7], (&(*grp)[MC_G7]));
  93         err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0]));
  94         err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1]));
  95         err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2]));
  96         err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3]));
  97         err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4]));
  98         err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5]));
  99         err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6]));
 100         err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7]));
 101
 102         err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp));
 103         err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7));
 104         err |= __put_user(fp,
 105               (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
 106         err |= __put_user(i7,
 107               (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
 108
 109         err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab));
 110         if (fenab) {
 111                 unsigned long *fpregs = current_thread_info()->fpregs;
 112                 unsigned long fprs;
 113
 114                 fprs_write(0);
 115                 err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs));
 116                 if (fprs & FPRS_DL)
 117                         err |= copy_from_user(fpregs,
 118                                               &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs),
 119                                               (sizeof(unsigned int) * 32));
 120                 if (fprs & FPRS_DU)
 121                         err |= copy_from_user(fpregs+16,
 122                          ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16,
 123                          (sizeof(unsigned int) * 32));
 124                 err |= __get_user(current_thread_info()->xfsr[0],
 125                                   &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr));
 126                 err |= __get_user(current_thread_info()->gsr[0],
 127                                   &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr));
 128                 regs->tstate &= ~TSTATE_PEF;
 129         }
 130         if (err)
 131                 goto do_sigsegv;
 132
 133         return;
 134 do_sigsegv:
 135         force_sig(SIGSEGV, current);
 136 }
 137
 138 asmlinkage void sparc64_get_context(struct pt_regs *regs)
 139 {
 140         struct ucontext __user *ucp = (struct ucontext __user *)
 141                 regs->u_regs[UREG_I0];
 142         mc_gregset_t __user *grp;
 143         mcontext_t __user *mcp;
 144         unsigned long fp, i7;
 145         unsigned char fenab;
 146         int err;
 147
 148         synchronize_user_stack();
 149         if (get_thread_wsaved() || clear_user(ucp, sizeof(*ucp)))
 150                 goto do_sigsegv;
 151
 152 #if 1
 153         fenab = 0; /* IMO get_context is like any other system call, thus modifies FPU state -jj */
 154 #else
 155         fenab = (current_thread_info()->fpsaved[0] & FPRS_FEF);
 156 #endif
 157
 158         mcp = &ucp->uc_mcontext;
 159         grp = &mcp->mc_gregs;
 160
 161         /* Skip over the trap instruction, first. */
 162         if (test_thread_flag(TIF_32BIT)) {
 163                 regs->tpc   = (regs->tnpc & 0xffffffff);
 164                 regs->tnpc  = (regs->tnpc + 4) & 0xffffffff;
 165         } else {
 166                 regs->tpc   = regs->tnpc;
 167                 regs->tnpc += 4;
 168         }
 169         err = 0;
 170         if (_NSIG_WORDS == 1)
 171                 err |= __put_user(current->blocked.sig[0],
 172                                   (unsigned long __user *)&ucp->uc_sigmask);
 173         else
 174                 err |= __copy_to_user(&ucp->uc_sigmask, &current->blocked,
 175                                       sizeof(sigset_t));
 176
 177         err |= __put_user(regs->tstate, &((*grp)[MC_TSTATE]));
 178         err |= __put_user(regs->tpc, &((*grp)[MC_PC]));
 179         err |= __put_user(regs->tnpc, &((*grp)[MC_NPC]));
 180         err |= __put_user(regs->y, &((*grp)[MC_Y]));
 181         err |= __put_user(regs->u_regs[UREG_G1], &((*grp)[MC_G1]));
 182         err |= __put_user(regs->u_regs[UREG_G2], &((*grp)[MC_G2]));
 183         err |= __put_user(regs->u_regs[UREG_G3], &((*grp)[MC_G3]));
 184         err |= __put_user(regs->u_regs[UREG_G4], &((*grp)[MC_G4]));
 185         err |= __put_user(regs->u_regs[UREG_G5], &((*grp)[MC_G5]));
 186         err |= __put_user(regs->u_regs[UREG_G6], &((*grp)[MC_G6]));
 187         err |= __put_user(regs->u_regs[UREG_G7], &((*grp)[MC_G7]));
 188         err |= __put_user(regs->u_regs[UREG_I0], &((*grp)[MC_O0]));
 189         err |= __put_user(regs->u_regs[UREG_I1], &((*grp)[MC_O1]));
 190         err |= __put_user(regs->u_regs[UREG_I2], &((*grp)[MC_O2]));
 191         err |= __put_user(regs->u_regs[UREG_I3], &((*grp)[MC_O3]));
 192         err |= __put_user(regs->u_regs[UREG_I4], &((*grp)[MC_O4]));
 193         err |= __put_user(regs->u_regs[UREG_I5], &((*grp)[MC_O5]));
 194         err |= __put_user(regs->u_regs[UREG_I6], &((*grp)[MC_O6]));
 195         err |= __put_user(regs->u_regs[UREG_I7], &((*grp)[MC_O7]));
 196
 197         err |= __get_user(fp,
 198                  (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
 199         err |= __get_user(i7,
 200                  (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
 201         err |= __put_user(fp, &(mcp->mc_fp));
 202         err |= __put_user(i7, &(mcp->mc_i7));
 203
 204         err |= __put_user(fenab, &(mcp->mc_fpregs.mcfpu_enab));
 205         if (fenab) {
 206                 unsigned long *fpregs = current_thread_info()->fpregs;
 207                 unsigned long fprs;
 208
 209                 fprs = current_thread_info()->fpsaved[0];
 210                 if (fprs & FPRS_DL)
 211                         err |= copy_to_user(&(mcp->mc_fpregs.mcfpu_fregs), fpregs,
 212                                             (sizeof(unsigned int) * 32));
 213                 if (fprs & FPRS_DU)
 214                         err |= copy_to_user(
 215                           ((unsigned long __user *)&(mcp->mc_fpregs.mcfpu_fregs))+16, fpregs+16,
 216                           (sizeof(unsigned int) * 32));
 217                 err |= __put_user(current_thread_info()->xfsr[0], &(mcp->mc_fpregs.mcfpu_fsr));
 218                 err |= __put_user(current_thread_info()->gsr[0], &(mcp->mc_fpregs.mcfpu_gsr));
 219                 err |= __put_user(fprs, &(mcp->mc_fpregs.mcfpu_fprs));
 220         }
 221         if (err)
 222                 goto do_sigsegv;
 223
 224         return;
 225 do_sigsegv:
 226         force_sig(SIGSEGV, current);
 227 }
 228
 229 struct rt_signal_frame {
 230         struct sparc_stackf     ss;
 231         siginfo_t               info;
 232         struct pt_regs          regs;
 233         __siginfo_fpu_t __user  *fpu_save;
 234         stack_t                 stack;
 235         sigset_t                mask;
 236         __siginfo_fpu_t         fpu_state;
 237 };
 238
 239 static long _sigpause_common(old_sigset_t set)
 240 {
 241         set &= _BLOCKABLE;
 242         spin_lock_irq(&current->sighand->siglock);
 243         current->saved_sigmask = current->blocked;
 244         siginitset(&current->blocked, set);
 245         recalc_sigpending();
 246         spin_unlock_irq(&current->sighand->siglock);
 247
 248         current->state = TASK_INTERRUPTIBLE;
 249         schedule();
 250         set_thread_flag(TIF_RESTORE_SIGMASK);
 251         return -ERESTARTNOHAND;
 252 }
 253
 254 asmlinkage long sys_sigpause(unsigned int set)
 255 {
 256         return _sigpause_common(set);
 257 }
 258
 259 asmlinkage long sys_sigsuspend(old_sigset_t set)
 260 {
 261         return _sigpause_common(set);
 262 }
 263
 264 static inline int
 265 restore_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
 266 {
 267         unsigned long *fpregs = current_thread_info()->fpregs;
 268         unsigned long fprs;
 269         int err;
 270
 271         err = __get_user(fprs, &fpu->si_fprs);
 272         fprs_write(0);
 273         regs->tstate &= ~TSTATE_PEF;
 274         if (fprs & FPRS_DL)
 275                 err |= copy_from_user(fpregs, &fpu->si_float_regs[0],
 276                                (sizeof(unsigned int) * 32));
 277         if (fprs & FPRS_DU)
 278                 err |= copy_from_user(fpregs+16, &fpu->si_float_regs[32],
 279                                (sizeof(unsigned int) * 32));
 280         err |= __get_user(current_thread_info()->xfsr[0], &fpu->si_fsr);
 281         err |= __get_user(current_thread_info()->gsr[0], &fpu->si_gsr);
 282         current_thread_info()->fpsaved[0] |= fprs;
 283         return err;
 284 }
 285
 286 void do_rt_sigreturn(struct pt_regs *regs)
 287 {
 288         struct rt_signal_frame __user *sf;
 289         unsigned long tpc, tnpc, tstate;
 290         __siginfo_fpu_t __user *fpu_save;
 291         sigset_t set;
 292         int err;
 293
 294         /* Always make any pending restarted system calls return -EINTR */
 295         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 296
 297         synchronize_user_stack ();
 298         sf = (struct rt_signal_frame __user *)
 299                 (regs->u_regs [UREG_FP] + STACK_BIAS);
 300
 301         /* 1. Make sure we are not getting garbage from the user */
 302         if (((unsigned long) sf) & 3)
 303                 goto segv;
 304
 305         err = get_user(tpc, &sf->regs.tpc);
 306         err |= __get_user(tnpc, &sf->regs.tnpc);
 307         if (test_thread_flag(TIF_32BIT)) {
 308                 tpc &= 0xffffffff;
 309                 tnpc &= 0xffffffff;
 310         }
 311         err |= ((tpc | tnpc) & 3);
 312
 313         /* 2. Restore the state */
 314         err |= __get_user(regs->y, &sf->regs.y);
 315         err |= __get_user(tstate, &sf->regs.tstate);
 316         err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs));
 317
 318         /* User can only change condition codes and %asi in %tstate. */
 319         regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
 320         regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
 321
 322         err |= __get_user(fpu_save, &sf->fpu_save);
 323         if (fpu_save)
 324                 err |= restore_fpu_state(regs, &sf->fpu_state);
 325
 326         err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
 327         err |= do_sigaltstack(&sf->stack, NULL, (unsigned long)sf);
 328
 329         if (err)
 330                 goto segv;
 331
 332         regs->tpc = tpc;
 333         regs->tnpc = tnpc;
 334
 335         /* Prevent syscall restart.  */
 336         pt_regs_clear_syscall(regs);
 337
 338         sigdelsetmask(&set, ~_BLOCKABLE);
 339         spin_lock_irq(&current->sighand->siglock);
 340         current->blocked = set;
 341         recalc_sigpending();
 342         spin_unlock_irq(&current->sighand->siglock);
 343         return;
 344 segv:
 345         force_sig(SIGSEGV, current);
 346 }
 347
 348 /* Checks if the fp is valid */
 349 static int invalid_frame_pointer(void __user *fp, int fplen)
 350 {
 351         if (((unsigned long) fp) & 7)
 352                 return 1;
 353         return 0;
 354 }
 355
 356 static inline int
 357 save_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
 358 {
 359         unsigned long *fpregs = current_thread_info()->fpregs;
 360         unsigned long fprs;
 361         int err = 0;
 362
 363         fprs = current_thread_info()->fpsaved[0];
 364         if (fprs & FPRS_DL)
 365                 err |= copy_to_user(&fpu->si_float_regs[0], fpregs,
 366                                     (sizeof(unsigned int) * 32));
 367         if (fprs & FPRS_DU)
 368                 err |= copy_to_user(&fpu->si_float_regs[32], fpregs+16,
 369                                     (sizeof(unsigned int) * 32));
 370         err |= __put_user(current_thread_info()->xfsr[0], &fpu->si_fsr);
 371         err |= __put_user(current_thread_info()->gsr[0], &fpu->si_gsr);
 372         err |= __put_user(fprs, &fpu->si_fprs);
 373
 374         return err;
 375 }
 376
 377 static inline void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, unsigned long framesize)
 378 {
 379         unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;
 380
 381         /*
 382          * If we are on the alternate signal stack and would overflow it, don't.
 383          * Return an always-bogus address instead so we will die with SIGSEGV.
 384          */
 385         if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
 386                 return (void __user *) -1L;
 387
 388         /* This is the X/Open sanctioned signal stack switching.  */
 389         if (ka->sa.sa_flags & SA_ONSTACK) {
 390                 if (sas_ss_flags(sp) == 0)
 391                         sp = current->sas_ss_sp + current->sas_ss_size;
 392         }
 393
 394         /* Always align the stack frame.  This handles two cases.  First,
 395          * sigaltstack need not be mindful of platform specific stack
 396          * alignment.  Second, if we took this signal because the stack
 397          * is not aligned properly, we'd like to take the signal cleanly
 398          * and report that.
 399          */
 400         sp &= ~7UL;
 401
 402         return (void __user *)(sp - framesize);
 403 }
 404
 405 static inline void
 406 setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
 407                int signo, sigset_t *oldset, siginfo_t *info)
 408 {
 409         struct rt_signal_frame __user *sf;
 410         int sigframe_size, err;
 411
 412         /* 1. Make sure everything is clean */
 413         synchronize_user_stack();
 414         save_and_clear_fpu();
 415
 416         sigframe_size = sizeof(struct rt_signal_frame);
 417         if (!(current_thread_info()->fpsaved[0] & FPRS_FEF))
 418                 sigframe_size -= sizeof(__siginfo_fpu_t);
 419
 420         sf = (struct rt_signal_frame __user *)
 421                 get_sigframe(ka, regs, sigframe_size);
 422
 423         if (invalid_frame_pointer (sf, sigframe_size))
 424                 goto sigill;
 425
 426         if (get_thread_wsaved() != 0)
 427                 goto sigill;
 428
 429         /* 2. Save the current process state */
 430         err = copy_to_user(&sf->regs, regs, sizeof (*regs));
 431
 432         if (current_thread_info()->fpsaved[0] & FPRS_FEF) {
 433                 err |= save_fpu_state(regs, &sf->fpu_state);
 434                 err |= __put_user((u64)&sf->fpu_state, &sf->fpu_save);
 435         } else {
 436                 err |= __put_user(0, &sf->fpu_save);
 437         }
 438
 439         /* Setup sigaltstack */
 440         err |= __put_user(current->sas_ss_sp, &sf->stack.ss_sp);
 441         err |= __put_user(sas_ss_flags(regs->u_regs[UREG_FP]), &sf->stack.ss_flags);
 442         err |= __put_user(current->sas_ss_size, &sf->stack.ss_size);
 443
 444         err |= copy_to_user(&sf->mask, oldset, sizeof(sigset_t));
 445
 446         err |= copy_in_user((u64 __user *)sf,
 447                             (u64 __user *)(regs->u_regs[UREG_FP]+STACK_BIAS),
 448                             sizeof(struct reg_window));
 449
 450         if (info)
 451                 err |= copy_siginfo_to_user(&sf->info, info);
 452         else {
 453                 err |= __put_user(signo, &sf->info.si_signo);
 454                 err |= __put_user(SI_NOINFO, &sf->info.si_code);
 455         }
 456         if (err)
 457                 goto sigsegv;
 458
 459         /* 3. signal handler back-trampoline and parameters */
 460         regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;
 461         regs->u_regs[UREG_I0] = signo;
 462         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
 463
 464         /* The sigcontext is passed in this way because of how it
 465          * is defined in GLIBC's /usr/include/bits/sigcontext.h
 466          * for sparc64.  It includes the 128 bytes of siginfo_t.
 467          */
 468         regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
 469
 470         /* 5. signal handler */
 471         regs->tpc = (unsigned long) ka->sa.sa_handler;
 472         regs->tnpc = (regs->tpc + 4);
 473         if (test_thread_flag(TIF_32BIT)) {
 474                 regs->tpc &= 0xffffffff;
 475                 regs->tnpc &= 0xffffffff;
 476         }
 477         /* 4. return to kernel instructions */
 478         regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
 479         return;
 480
 481 sigill:
 482         do_exit(SIGILL);
 483 sigsegv:
 484         force_sigsegv(signo, current);
 485 }
 486
 487 static inline void handle_signal(unsigned long signr, struct k_sigaction *ka,
 488                                  siginfo_t *info,
 489                                  sigset_t *oldset, struct pt_regs *regs)
 490 {
 491         setup_rt_frame(ka, regs, signr, oldset,
 492                        (ka->sa.sa_flags & SA_SIGINFO) ? info : NULL);
 493         spin_lock_irq(&current->sighand->siglock);
 494         sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 495         if (!(ka->sa.sa_flags & SA_NOMASK))
 496                 sigaddset(&current->blocked,signr);
 497         recalc_sigpending();
 498         spin_unlock_irq(&current->sighand->siglock);
 499 }
 500
 501 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
 502                                    struct sigaction *sa)
 503 {
 504         switch (regs->u_regs[UREG_I0]) {
 505         case ERESTART_RESTARTBLOCK:
 506         case ERESTARTNOHAND:
 507         no_system_call_restart:
 508                 regs->u_regs[UREG_I0] = EINTR;
 509                 regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY);
 510                 break;
 511         case ERESTARTSYS:
 512                 if (!(sa->sa_flags & SA_RESTART))
 513                         goto no_system_call_restart;
 514                 /* fallthrough */
 515         case ERESTARTNOINTR:
 516                 regs->u_regs[UREG_I0] = orig_i0;
 517                 regs->tpc -= 4;
 518                 regs->tnpc -= 4;
 519         }
 520 }
 521
 522 /* Note that 'init' is a special process: it doesn't get signals it doesn't
 523  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 524  * mistake.
 525  */
 526 static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
 527 {
 528         struct k_sigaction ka;
 529         int restart_syscall;
 530         sigset_t *oldset;
 531         siginfo_t info;
 532         int signr;
 533
 534         if (pt_regs_is_syscall(regs) &&
 535             (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
 536                 restart_syscall = 1;
 537         } else
 538                 restart_syscall = 0;
 539
 540         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 541                 oldset = &current->saved_sigmask;
 542         else
 543                 oldset = &current->blocked;
 544
 545 #ifdef CONFIG_COMPAT
 546         if (test_thread_flag(TIF_32BIT)) {
 547                 extern void do_signal32(sigset_t *, struct pt_regs *,
 548                                         int restart_syscall,
 549                                         unsigned long orig_i0);
 550                 do_signal32(oldset, regs, restart_syscall, orig_i0);
 551                 return;
 552         }
 553 #endif
 554
 555         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 556
 557         /* If the debugger messes with the program counter, it clears
 558          * the software "in syscall" bit, directing us to not perform
 559          * a syscall restart.
 560          */
 561         if (restart_syscall && !pt_regs_is_syscall(regs))
 562                 restart_syscall = 0;
 563
 564         if (signr > 0) {
 565                 if (restart_syscall)
 566                         syscall_restart(orig_i0, regs, &ka.sa);
 567                 handle_signal(signr, &ka, &info, oldset, regs);
 568
 569                 /* a signal was successfully delivered; the saved
 570                  * sigmask will have been stored in the signal frame,
 571                  * and will be restored by sigreturn, so we can simply
 572                  * clear the TIF_RESTORE_SIGMASK flag.
 573                  */
 574                 if (test_thread_flag(TIF_RESTORE_SIGMASK))
 575                         clear_thread_flag(TIF_RESTORE_SIGMASK);
 576                 return;
 577         }
 578         if (restart_syscall &&
 579             (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
 580              regs->u_regs[UREG_I0] == ERESTARTSYS ||
 581              regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
 582                 /* replay the system call when we are done */
 583                 regs->u_regs[UREG_I0] = orig_i0;
 584                 regs->tpc -= 4;
 585                 regs->tnpc -= 4;
 586         }
 587         if (restart_syscall &&
 588             regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
 589                 regs->u_regs[UREG_G1] = __NR_restart_syscall;
 590                 regs->tpc -= 4;
 591                 regs->tnpc -= 4;
 592         }
 593
 594         /* if there's no signal to deliver, we just put the saved sigmask
 595          * back
 596          */
 597         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 598                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 599                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 600         }
 601 }
 602
 603 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags)
 604 {
 605         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 606                 do_signal(regs, orig_i0);
 607 }